1. A. Field of the Invention
The present invention relates to a device comprising a hinged cover which is pivotable about an axis of rotation out of a closed final position into an open final position, and a flexible element which acts on the hinged cover with a force along a spring line of action. The flexible element is axially loaded in at least one final position of the hinged cover and is loaded with transverse forces in bending or extension in at least one further position. In the open position of the cover, the spring line of action approaches the axis of rotation of the cover or lies substantially on the axis of rotation of the hinged cover such that the cover can be fixed in the open final position. Alternatively, in the open position of the cover, the spring line of action coincides with the axis of rotation of the cover such that the cover can be fixed in the open final position. The invention also relates to an electrical power socket, which is covered by a spring-loaded hinged cover and comprises a device according to the invention.
2. B. Related Art
The present invention is preferentially but not exclusively used for electric sockets which have a spring loaded rotational cover for the protection against external influences.
Self-closing spring-loaded hinged covers are often used for the protection of electric sockets. In particular vehicles, for example delivery vans, can be equipped with such a socket whose insertion opening is located on the outside of the vehicle for the purpose of supplying energy to a towed vehicle or using an externally located electric motor. A self-closing spring-loaded hinged cover is employed on such a socket in order to prevent the entry of water and dust through the insertion opening. Using a spiral cylindrical torsion spring in such a vehicle socket cover subjects the hinged cover to a force in the closing direction, which safely closes the insertion opening when the socket is not in use.
For example, DE 38 09 289 A1 describes the socket of an electrical connection pair for the electrical connection of trailer and its towing vehicle, whereby the hinged cover of the socket automatically closes when the plug is disengaged by means of a spring connected to the socket housing on one end, while the spring engages with a free bracket in the middle part of the hinged cover on the other end.
When using a coil spring, the force, which acts on a hinged cover, is greater when the hinged cover is open and weaker when the hinged cover is closed. When such a device is used outside, the active force or preloading force of the spring is very strong such that the hinged cover is held in a closed position and can't move in the opening direction due to the effects of the injection pressure used in high pressure washing water or caused by vibrations during driving. However, the maximum preloading force of the spring is limited by the risk of injury to the user.
To circumvent this problem, DE 10 2004 056 009 A1 proposes a vehicle socket cover, comprising torsion coil springs which act with a force on the cover, and sliding contact surfaces to dampen the active forces. Therefore, the hinged cover and a cover main body comprise several sliding-contact surfaces, being constrained into a force-closed roll-side joint and a sliding contact, immediately prior to the hinged cover reaching its closed position, resulting in a deviated path of the hinged cover from its opening position to its closing position. However, this requires a comparatively complicated mechanical structure.
DE 18 80 788 U is also known from the prior art. This invention relates to a cover plate that is equipped with a hinged cover and is particularly used for sockets in order to protect them from moisture and to attach them to the cover plate both discreetly and reliably. The cover plate having a rectangular shape and a removable closing spring in the form of a cylindrical coil spring being attached to the cover plate and the hinged cover by inserted pins. The disadvantage of this is that a hinged cover of this kind isn't provided with a defined opening position, and the helical spring would be over-twisted and deformed by exceeding the open position.
From DE 76 00 675 U, a plug coupling that provides a lockable socket lid and a lockable coupling state. This prior art specifically discloses a connection coupling that provides a closeable simple locking system in order to not only lock the socket lid closed in the decoupled state, but also to prevent the removal or loss of the plug from the connection in the coupled state by using the same key; both functions are achieved utilizing a locking body that is pivotable against a first spring. Hence, DE 76 00 675 U shows a device with a special key that can control a socket lid.
Document DE 11 41 714 A also relates to the prior art and describes a tubular wall light with a socket, that is attached to a bulkhead and closed by a hinged cover. The main disadvantage of this invention is the fact that the cover cannot be fixed open without the use of a foreign object, so that the spring element would be damaged.
U.S. Pat. No. 4,036,396 A describes a conduit box whose cover is connected to a coil spring and contains a bean-shaped slot for the rotational axis R which is obviously supposed to enable a corresponding control of the cover which would allow it to be fixed in position. Because of the bean-shaped slot for the axis of rotation, the cover has to be manually attached to the axis of rotation. The disadvantage of this is that the cover also has to be manually released from its position. Therefore, the user has to manually manipulate the attached cover in a way that the rotational axis of the cover is free to rotate again. The disadvantage of this is the fact that it isn't possible to control the position of the cover without a manual adjustment so that it can be fixed in an open position.
Another invention known from the prior art is DE 88 00 544 U1 which relates to a cover plate that is equipped with a hinged cover for the purpose of protecting a socket from moisture, using a closing spring which acts upon the cover.
Every device known from the prior art generally are characterized by the fact that the spring is not limited and would be deformed in case of inappropriate usage. Another disadvantage is the fact most devices known from the prior art can only be used to close a hinged cover. The hinged cover cannot be fixed in an open position, or the hinged cover can only be fixed in an open position if the user unhinges the axis of rotation, using, for example, a bean-shaped slot as described above.
By using special designs (adjustable wind diameter, molded rubber parts, air springs) springs whose force-distance relationship is not linear can be produced. Using nonlinear springs has the advantage that the spring rate changes depending on the deformation of the spring. Shock-absorbing springs often act progressively which means that the spring force increases disproportionably to the compression of the spring. This prevents, for example, the spring from blocking against itself and accelerates the decay of oscillations. This is particularly desirable in the automotive industry. For example, stacked leaf springs and cone-shaped coil springs provide this characteristic. Springs with a digressive spring characteristic become softer with increasing load. This is desirable if another longer spring travel with a smaller increase in force after a certain loading is required. Digressive springs are for example rubber springs or tensile-loaded springs.